Generally, there has been a need for increasing the speed at which computer programs are executed. A computer typically has at least one processor running instructions that make up a computer program. In what is known as sequential or serial processing, the instructions that make up a computer program are executed one at a time by a processor of a computer. That is, a first instruction is executed, then a second instruction is executed, and so forth, until the program is finished. Therefore, in sequential or serial processing, the execution speed of programs can be increased by increasing the speed at which the processor of the computer executes instructions.
In another type of processing, known as parallel processing, increased program execution speed is achieved by executing program instructions in parallel with one another. Thus, for example, a first instruction may be executed by a first processor of the computer at the same time a second instruction is executed by a second processor (or, a different part of the first processor), then a third instruction may be executed by the first processor at the same time as a fourth instruction is executed by the second processor (or, the different part of the first processor), etc.
Parallel processing is not as commonly-used as sequential processing. Computer programmers, for example, are typically not as experienced in developing computer programs that take advantage of parallel processing as they are in writing programs that are to be processed sequentially. Thus, there has generally been more emphasis placed on increasing the speed of processors themselves to achieve increased execution speed of computer programs, rather than on utilizing parallel processing to achieve increased execution speed of computer programs.